JP4152285B2 - Granulation method for sintered raw materials for iron making - Google Patents

Description

The present invention relates to a method for granulating a sintering raw material for iron making (hereinafter also referred to as a sintering raw material). More specifically, the present invention relates to a method for granulating a sintered raw material for pre-processing fine iron ore and the like in a manufacturing process of sintered ore that is a raw material for charging a blast furnace in a iron making process.

The iron making process is generally performed by charging sintered ore made of iron ore, lump ore, and pellets together with coke into a blast furnace. This sintered ore is pre-processed with sintering raw materials including iron ore, auxiliary raw materials, fuel, etc., filled in a sintering machine to a specific height to form a sintering bed, and then fired by firing the surface layer It is manufactured by doing. As a sintering machine, a downward suction type is usually adopted, and air necessary for sintering is circulated by suctioning from below the sintering raw material, and fuel is supplied downward from above the sintering raw material. By burning, the sintering raw material is sintered. For this reason, if the sintering raw material contains a lot of fine powder, the air permeability decreases due to clogging and the like, and the combustion rate of coke, which is the fuel, becomes slow, so the production efficiency of the sintered ore decreases. It becomes.

Therefore, in order to improve the air permeability in the sintering machine and improve the productivity, a pretreatment such as granulating the sintered raw material to form pseudo particles is performed. For example, granulation operations such as mixing iron ore as a raw material for sintering, auxiliary materials, fuel, and the like, adding a small amount of water, and stirring with a granulator are performed. Pseudo particles are particles in which fine particles of 0.5 mm or less are generally attached to 1 to 3 mm core particles. The actions required for such granulation are to improve the quasi-granulating property in which fine particles adhere to the periphery of the core particles, and to make the quasi-particles difficult to collapse in the sintering process.
Recently, with the depletion of excellent agglomerates, the deterioration of powdered ore has also become severe, and the granulation properties of sintered raw materials tend to be worse than before. Technology that is highly effective is highly desired.

In the pretreatment of such a sintering raw material, the granulation operation using only water has a poor effect of improving the pseudo-granulating property, and therefore the amount of fine powder contained in the sintering raw material cannot be reduced so much. For this reason, as a countermeasure for improving the pseudo-granulating property, a method of adding a granulating additive having an action as a binder to the sintered raw material has been proposed. Quick lime is widely used as a granulating additive. Quick lime can promote the formation of pseudo-particles in the granulator, and also prevents the pseudo-particles from collapsing during the drying and heating process in the sintering process. It is said that the flow of

However, binders such as quick lime are generally relatively expensive, and quick lime easily absorbs moisture and generates heat at this time, so that easy to handle is required. Furthermore, since quick lime currently used cannot obtain a sufficient effect unless the amount used is relatively large, the cost also increases in this respect. In the case of using quicklime, the current situation is that the amount used is reduced as much as possible. And even if 2 mass% or more of quicklime is added, the improvement effect of the pseudo-granulation property tends to reach a peak.

As a conventional processing technology for sintered raw materials, a method for producing a sintered raw material for blast furnace by hydromixing coarse-grained iron ore and fine-grained iron ore according to the type of raw material. A method has been disclosed in which classification is performed based on a set classification point, and a fine auxiliary material is added and mixed in advance to the finely divided fine iron ore to form a pseudo-granular mass (see, for example, Patent Document 1). . In this method, granulation is performed by adding limestone having a particle size of 3 mm or less. However, in such addition of limestone, it is difficult to sufficiently add a fine powder portion effective for the collapse prevention effect. Therefore, in order to show sufficiently effective productivity in such a method, quick lime or the like is used. It was necessary to use a relatively large amount of binder (usually 1-2%). Further, the productivity improvement effect was not sufficient. In this respect, there was room for improvement to improve the productivity of sintered ore.

After mixing and granulating the sintering raw material excluding the granular fuel using a mixer with a built-in high-speed rotating blade, the granular fuel is added to the mixture, and the granulator has a rolling function. A method for granulating a sintered raw material characterized by granulating is described (for example, see Patent Document 2). In order to show effective productivity in such a method, it was necessary to use a relatively large amount of binder (usually 1-2%) such as quicklime. Further, the productivity improvement effect was not sufficient. In this respect, there was room for improvement to improve the productivity of sintered ore.

On the other hand, as another conventional granulation method of a sintering raw material, a treatment method using a polymer compound such as polyacrylic acid as a binder for granulation of iron ore containing fine iron ore is known (for example, , See Patent Documents 3, 4, 5 and 6.) However, there is room for improvement in these methods. In these methods, the effect is not sufficient, and a relatively large amount of addition is required in order to obtain a sufficiently effective effect. This result is similarly applied to the combined system of polyacrylic acid or the like and fine powder such as calcium carbonate disclosed in Patent Document 6.

Moreover, the processing method which uses fine powders, such as a calcium carbonate, independently is also disclosed (for example, refer patent document 6). However, in general, these fine powders are used as an anti-disintegration agent that prevents the pseudo particles obtained by granulating the sintering raw material from collapsing during sintering. However, it is difficult to uniformly disperse the raw material for iron making during granulation, and the effect of preventing the spurious particles from collapsing cannot be exhibited sufficiently. In addition, these fine powders themselves do not have the effect of improving the granulation property of the sintered raw material, that is, the effect of improving the pseudo-granulating property, and it is difficult to sufficiently uniformly mix the whole sintered raw material. However, it is not possible to expect a sufficiently effective productivity improvement, and there is room for improvement in this respect. In addition, it is known that the degree of pseudo-granulation can be improved by granulating using a large amount of water, but the use of a large amount of water is aeration in the moisture condensation zone in the sintering bed. In order to adversely affect the operation of the sintering machine because of increasing the resistance or the like, the sintering raw material moisture after granulation is usually set to 6 to 8%.
Japanese Patent Publication No. 63-20288 (first and fourth pages) Japanese Patent No. 3058015 (first page) JP 59-50129 (page 1-3) JP-A-61-61630 (first page) JP 10-502417 A (page 1-3) International Publication No. 02/066688 pamphlet (pages 155-159)

The present invention has been made in view of the above situation, and is effective for granulating a sintered raw material for iron making, such as fine iron ore, in the production of sintered ore as a raw material for charging a blast furnace in the iron making process, It is possible to suppress the amount of binder added less than the amount of binder required when granulating all the raw materials for iron making at once, and even when only fine powder is used in the selective granulation process Is improved, and after the selective granulation step, a granulation treatment step comprising a step of mixing the granulated product obtained by the step with the remaining sintering raw material for iron making, without using a binder such as quick lime, Alternatively, an object of the present invention is to provide a method for granulating a sintered raw material for iron making which can realize sufficient sintered ore productivity even if the amount of binder added is suppressed.

While the inventors have variously studied granulation processing methods for granulating a sintered raw material for iron making, after the selective granulation step in which a part of the sintered raw material for iron making is preliminarily granulated, it is obtained by the step. Paying attention to the fact that the granulation of the sintered raw material for iron making can be improved by performing the granulation process including the step of mixing the resulting granulated product with the remaining sintering raw material for iron making, such a selective granulation step In the above, when a granulation treatment is performed using a polymer compound having a specific group as a granulating agent, the granulation property exhibited by the polymer compound is effectively exhibited, and fine particles having an average particle size of 200 μm or less are obtained. When the granulation treatment is used as a granulating agent, the effect of suppressing the collapse of the pseudo particles during the sintering exhibited by the fine particles is sufficiently exerted, and further, by using the polymer compound and the fine particles in combination, these To demonstrate synergistic effects It found that that can, and conceived that can be admirably solved the above problems. That is, when a part of the raw material for iron making sintering is selectively granulated, a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof, and / or Alternatively, by using fine particles having an average particle size of 200 μm or less, (1) granulation can be achieved with an addition amount smaller than the addition amount of the polymer compound required for granulating all the iron-making sintered raw materials at once. (2) In the selective granulation process, the moisture content is higher than the moisture after granulating the entire iron-making sintered raw material. In the case of using only fine particles, it is possible to adjust the moisture content of the sintered raw material after granulation to a normal range by reducing the amount of water added to the remaining sintering raw material. Improved granulation, (3 After the selective granulation step, in the granulation treatment step including the step of mixing the granulated product obtained by the step with the remaining sintering raw material for iron making, a binder such as quick lime is not used, or the amount of binder added is Even if it is suppressed, it has been found that the effects such as sufficient productivity of sintered ore can be realized, and the present invention has been achieved.

That is, in the present invention, when granulating a sintered raw material for iron making containing fine iron ore, after the selective granulation step of granulating a part of the sintered raw material for iron making in advance, the granulation obtained by the above step is performed. A method for granulating a sintered raw material for iron making comprising a step of mixing the granules with the remaining sintered raw material for iron making, wherein the selective granulating step comprises a carboxyl group, a sulfonic acid group and a salt thereof. It is a granulation method of a sintered raw material for iron making, which is obtained by granulating using a polymer compound having at least one group selected from the group consisting of and / or fine particles having an average particle size of 200 μm or less.
The present invention is described in detail below.

In the present invention, when granulating a sintered raw material for iron making containing fine iron ore, a selective granulation step of granulating a part of the sintered raw material in advance is performed. “Selection” in the selective granulation step is, for example, appropriately selecting a part of the sintered raw material for iron making so that it is efficiently granulated in the granulating method of the sintered raw material for iron making. In the case where a plurality of raw materials are used as a sintering raw material for iron making, a selective granulation step is performed by selecting a material to be granulated from a plurality of raw materials in advance.
The iron-making sintering raw material that is granulated in the selective granulation step includes (1) those that are difficult to be pseudo-particles, (2) those that can cause the pseudo-particles to collapse, and (3) combustion when sintered. It is preferable to select one containing a material that can cause a decrease in speed. Examples of such a raw material for iron making include a raw material containing a material containing a large amount of fine powder having a particle size of 1 mm or less, a porous material, a crystal water, a material containing a large amount of aluminum, and the like. . In addition, when selectively taking out the sintering raw material for iron making on the basis of the particle diameter, a method of classification using a sieve or the like is preferable.

Moreover, it is preferable that the sintering raw material for iron making granulated in such a selective granulation process contains 5-60 mass% of the sintering raw material for all iron making. More preferably, it is 12 mass% or more and 45 mass% or less. Most preferably, it is 15 mass% or more and 30 mass% or less. If the amount is less than 5% by mass, the ratio of the sintering raw material for iron making to the total amount of the sintering raw material for iron making is reduced in comparison with the case where the sintering raw material for iron making is granulated at once. Therefore, the productivity improvement effect tends to be difficult to see. On the other hand, when it exceeds 60% by mass, the ratio of the sintered raw material for iron making processed in the selective granulation step to the total amount of the raw material for iron making sintering is increased, due to a decrease in granulation property in the selective granulation step, etc. Also, compared with the case where the sintering raw material for iron making is granulated at once, the productivity improvement effect tends to be less visible.
In the present specification, the amount of raw materials (iron ore, secondary materials for iron making, fuel, fine particles, granulating agents, etc.) used in the method for granulating sintered raw materials for iron making is determined by the use of these raw materials. It is the value when converted into a completely dry state (absolute dry conversion). In the present invention, for mass calculation, fine particles and a granulating agent are also included in the sintering raw material for iron making.

In the selective granulation step, a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof, and / or fine particles having an average particle size of 200 μm or less are used. It will be granulated. The form using such a polymer compound or fine particles is not particularly limited, and may be added to the sintering raw material for iron making in the selective granulation step once or may be added in a plurality of times. In the selective granulation step, a granulating agent as described later may be used in combination.

When using the polymer compound, the amount used in the selective granulation step may be appropriately set according to the granulation properties of the sintering raw material, the type of the polymer compound, the type of apparatus used, etc. , Sintering raw materials for all iron making (including iron ore, auxiliary raw materials, fuel, fine particles, granulating agent) in a mass ratio to 100% by mass so that the polymer compound is 0.001% by mass or more. Is preferable, and it is preferable to be 1% by mass or less. If the amount is less than 0.001% by mass, the effects of the present invention may not be sufficiently exerted. If the amount exceeds 1% by mass, the polymer compound for the iron-making sintered raw material in the selective granulation step There is a risk that problems such as excessive addition amount, large formation of sintered raw materials for iron making, and difficulty in sintering. More preferably, the polymer compound is 0.003% by mass or more, and 0.5% by mass or less.
The timing of adding the polymer compound may be before the selective granulation step or during the selective granulation step, or may be a combination thereof.
The polymer compound may be further added after the selective granulation step. In this case, the amount of the polymer compound used, that is, the amount used in the selective granulation step and the selective granulation step. The total amount added after is preferably 0.006% by mass or more, and preferably 1% by mass or less.
In addition, the said 100 mass% of all raw materials for iron-making sintering is a value when a raw material is completely dried.

In the present invention, iron ore having an average particle diameter of 200 μm or less, dust generated in an iron mill having an average particle diameter of 200 μm or less, and slag generated in an iron mill having an average particle diameter of 200 μm or less can be used as the fine particles. However, since these dispersibility is not sufficient, the productivity improvement effect is small, which is not preferable. When these are used as the fine particles, the selective granulation step is preferably performed using a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a salt thereof in combination. It is preferable.
Thus, when granulating the sintered raw material for iron making containing fine iron ore, the granulation obtained by the above step after the selective granulation step of granulating a part of the sintered raw material for iron making in advance. A method for granulating a sintered raw material for iron making comprising mixing a product with the remaining sintered raw material for iron making, wherein the selective granulating step comprises a carboxyl group, a sulfonic acid group and a salt thereof. A polymer compound having at least one group selected from the group, fine particles having an average particle diameter of 200 μm or less, iron ore having an average particle diameter of 200 μm or less, dust generated in a steel mill having an average particle diameter of 200 μm or less, and A method for granulating a sintered raw material for iron making which is granulated using at least one kind of fine particles selected from the group consisting of slag generated in an iron mill having an average particle size of 200 μm or less is also one aspect of the present invention. One

The amount of fine particles having an average particle size of 200 μm or less in the selective granulation is as follows. The fine particles are iron ore having an average particle size of 200 μm or less, dust generated in an iron mill having an average particle size of 200 μm or less, and the average particle size is The sum total of those excluding slag generated in an iron mill of 200 μm or less is a mass ratio with respect to 100 mass% of the total raw material for iron making, preferably 0.05 mass% or more, and preferably 10 mass% or less. When the amount is less than 0.05% by mass, the effect of improving the quasi-granulating property and suppressing the collapse of the quasi-particles may not be sufficiently improved. On the other hand, when the content is more than 10% by mass, the cohesive force of the raw material becomes too high in the selective granulation step, and a large lump is generated, which may make sintering difficult.
In addition to the fine particles, iron ore having an average particle size of 200 μm or less, dust generated in an ironworks having an average particle size of 200 μm or less, and slag generated in an ironworks having an average particle size of 200 μm or less may be added.
The timing of adding the fine particles may be before the selective granulation step or during the selective granulation step, or may be a combination thereof.
The fine particles may be further added after the selective granulation step. In this case, the amount of the fine particles used, that is, the amount used in the selective granulation step and the addition after the selective granulation step. The total amount is preferably 0.15% by mass or more, and more preferably 10% by mass or less.
In addition, the mass ratio of the sintering raw material for all iron making and the fine particles is a value when the sintering raw material for iron making and the fine particles are completely dried.

In addition, as the use amount of fine particles having an average particle size of 200 μm or less in the selective granulation, fine particles having an average particle size of 200 μm or less are iron ores having an average particle size of 200 μm or less, and in an iron mill having an average particle size of 200 μm or less. When the generated dust and the slag generated in an iron mill having an average particle size of 200 μm or less are included, the mass ratio is preferably 0.05% by mass or more, and preferably 60% by mass or less, based on 100% by mass of the sintered raw material for iron making. . When the amount is less than 0.05% by mass, the effect of improving the quasi-granulating property and suppressing the collapse of the quasi-particles may not be sufficiently improved. On the other hand, when the amount is more than 60% by mass, a large amount of the polymer compound is required, so that the cost is significantly increased, which is not economically preferable.
In this case, the sum of fine particles having an average particle size of 200 μm or less excluding iron ore, dust generated in the steelworks, and slag generated in the steelworks can be 0% by mass, but the average particle size is 200 μm or less. The sum of iron ore, dust generated in an iron mill having an average particle diameter of 200 μm or less, and slag generated in an iron mill having an average particle diameter of 200 μm or less is a mass ratio of 100% by mass with respect to 100% by mass of all the iron-making sintered raw materials. It is preferable that it will be 05 mass% or more and 60 mass% or less.
In this case, the fine particles may be further added after the selective granulation step. In this case, however, the amount of the fine particles used, that is, the amount used in the selective granulation step and the selective granulation step. The total amount added after the process is preferably 0.15% by mass or more and 80% by mass or less, based on 100% by mass of the total iron-making sintering raw material. It is preferable to make it.

Preferred forms in the selective granulation step of the present invention include iron ore having an average particle size of 200 μm or less, dust generated in an ironworks having an average particle size of 200 μm or less, and slag generated in an ironworks having an average particle size of 200 μm or less. In the form of adding 0.05 to 10% by mass of fine particles having an average particle size of 200 μm or less, excluding, in a mass ratio with respect to 100% by mass of the total raw material for iron making, more preferably 0.1% by mass or more Yes, and more preferably 0.2% by mass or more. In addition, fine particles having an average particle diameter of 200 μm or less, including iron ore having an average particle diameter of 200 μm or less, dust generated in an ironworks having an average particle diameter of 200 μm or less, and slag generated in an ironworks having an average particle diameter of 200 μm or less. In addition, it is a form in which 0.05 to 60% by mass is added in a mass ratio with respect to 100% by mass of the raw material for sintering for iron making, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. It is.

In the selective granulation step of the present invention, the amount of the polymer compound added is 0 to 1% by mass with respect to 100% by mass of the total raw material for iron making sintering, and the iron ore having an average particle size of 200 μm or less. It is preferable that the addition amount of the above fine particles is 0.05 to 10% by mass except for stones, dust generated in an ironworks having an average particle size of 200 μm or less, and slag generated in an ironworks having an average particle size of 200 μm or less. It is. In addition, the iron ore having an average particle diameter of 200 μm or less, dust generated in an iron mill having an average particle diameter of 200 μm or less, and the addition amount of the above fine particles including slag generated in an iron mill having an average particle diameter of 200 μm or less are all iron manufacturing It is also a preferable embodiment that the mass ratio is 0 to 60% by mass with respect to 100% by mass of the sintering raw material, and the amount of the polymer compound added is 0.001 to 1% by mass.
The addition amount of the polymer compound or fine particles in the selective granulation step is the sum of the amounts added before and during the selective granulation step.

In the method for granulating a sintered raw material for iron making according to the present invention, after the selective granulation step, a step of mixing the granulated product obtained by the step (selective granulated product) with the remaining sintered raw material for iron making. Will be included. Therefore, the granulation process may be completed after passing through the mixing step, or pseudo-particle formation may proceed in the step of mixing together with the remaining sintered raw materials. In the step of mixing the selected granulated material together with the remaining sintering raw material, the entire remaining sintering raw material for iron making may be mixed, or the remaining part of the sintering raw material for iron making may be mixed multiple times. May be.

When granulating in the step of mixing the selected granulated material and the remaining sintered raw material, the granulation treatment may be performed using a granulation treatment agent, or the granulation treatment may be performed without using the granulation treatment agent. However, it is preferable to use a granulating agent. The granulation treatment agent means a compound or the like used for improving the granulation property when granulating a sintered raw material for iron making. The granulating agent used in the step of mixing the selected granulated product and the remaining sintering raw material is at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof in the present invention. And a polymer compound having an average particle diameter of 200 μm or less may be contained. It does not specifically limit as a form using such a granulation processing agent, You may add to the sintering raw material for iron manufacture in the process of mixing a selective granulated material and the remaining sintering raw material at once, or multiple times It may be added separately.

The granulating agent is selected from the group consisting of quicklime, bentonite, lignin sulfite (pulp waste liquor), starch, sugar, molasses, water glass, cement, gelatin, corn starch, carboxyl group, sulfonic acid group and salts thereof. One or more polymer compounds having at least one kind of group can be used, and among these, quick lime is preferably used.
The amount used in the step of mixing the above selected granulated product and the remaining sintered raw material (the amount used excluding the amount used in the above selective granulation step) is that the granulating agent is inorganic such as quicklime, bentonite, cement, etc. In the case of a compound, it is preferably 0.1 parts by weight or more with respect to 100 parts by weight of the sintered raw material for iron making in the step of mixing the selected granulated product and the remaining sintered raw material, and 5.0 parts by weight The following is preferable. More preferably, it is 0.3 parts by weight or more and 2.5 parts by weight or less. In the case where the granulating agent is an organic compound such as a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof, the selected granulated product and the remaining sintered raw material are used. It is preferable to set it as 0.005 weight part or more with respect to 100 weight part of sintering raw materials for iron manufacture in the process to mix, and it is preferable to set it as 1.0 weight part or less. More preferably, it is 0.01 parts by weight or more and 0.5 parts by weight or less.

The fine particles having an average particle size of 200 μm or less in the present invention may be fine particles having such an average particle size, but calcium carbonate, kaolin clay, silica, silica sand, talc, bentonite, dolomite powder, dolomite plaster , Magnesium carbonate, silica fume, anhydrous gypsum, sericite, montmorillonite, shirasu, shirasu balloon, diatomaceous earth, calcined diatomaceous earth, silicon carbide, yellow iron oxide, strontium carbonate, barium carbonate, graphite, wollastonite, crecas sphere, carbon black, Bengara, ground serpentine, activated clay, Portland cement, ground silica, magnesium oxide, calcined leech stone, dust generated in processes other than steelworks, specifically generated in thermal power plants such as fly ash and heavy oil ash In dust and copper making process Raw to Karami iron concentrate, copper slag, red mud discharged by alumina production processes, other a suitable flue gas desulfurization gypsum and asbestos dust, can be used alone or in combination. Preferably, it is at least one selected from the group consisting of calcium carbonate, fly ash, kaolin clay, silica, talc, bentonite, silica fume, and anhydrous gypsum. More preferred are calcium carbonate, fly ash and silica fume.

The average particle diameter of the fine particles having an average particle diameter of 200 μm or less is preferably 0.01 μm or more, and preferably 100 μm or less. More preferably, it is 0.02 μm or more and 50 μm or less. Most preferably, it is 0.1 μm or more and 20 μm or less. When the average particle diameter exceeds 200 μm, the ratio of large particles to which fine particles adhere is larger than the proportion of fine particles that have an effect of suppressing the decay of pseudo particles in a sintered bed, etc. It becomes difficult to obtain. On the other hand, when the thickness is less than 0.01 μm, the cohesive force of the fine particles becomes strong and it becomes difficult to disperse in the sintering raw material for iron making, so that the effect of addition is hardly obtained.
In the present invention, quick lime may be used as fine particles having an average particle size of 200 μm or less. Further, when a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a salt thereof is used as an essential component, preferable fine particles include iron ore having an average particle size of 200 μm or less, and iron making. Dust and slag generated in the station can also be used. Also in this case, the average particle diameter is preferably 0.01 μm or more and 100 μm or less. More preferably, it is 0.02 μm or more and 50 μm or less. Most preferably, it is 0.1 μm or more and 20 μm or less.

In the granulation treatment method of the present invention, (1) it is possible to improve granulation with an addition amount smaller than the addition amount of the polymer compound required when granulating all the sintered raw materials at once, Furthermore, the effect of significant granulation improvement can be seen. (2) In selective granulation, granulation can be performed with a higher moisture content than the moisture after granulating the entire sintered raw material (the remaining By reducing the moisture content of the sintering raw material, the moisture content during sintering can be adjusted to the normal range.) Even when only fine particles are used, improvement in granulation can be seen, (3) Selection In the step of mixing the granulated product obtained by the step with the remaining sintering raw material for iron making after the granulation step, sufficient production of sintered ore is achieved even if a binder such as quick lime is not used or the amount of binder added is suppressed. The effects such as the ability to be realized will be exhibited.

In the present invention, the above-mentioned effects can be sufficiently exerted even when a sintering raw material containing 10% by mass or more of a difficult granulating raw material in 100% by mass of the sintering raw material in the selective granulation step is used. Such a form is one of the preferred embodiments. More preferably, it contains 50 mass% or more, and still more preferably contains 80 mass% or more. 1 type (s) or 2 or more types can be used for a difficult granulation raw material.
The hardly granulated raw material is a raw material containing a large amount of maramamba ore, pellet feed, dust, limestone, fine powder of 1 mm or less.
In the present invention, the selective granulation step is a sintering raw material 100 in the selective granulation step selected from the group consisting of maramamba ore, pellet feed and a raw material containing 40% or more of fine powders of 1 mm or less. A form containing 10% by mass or more in% by mass is also one preferred embodiment.

The above-mentioned maramamba ore is a general term for iron ores produced from the maramanba iron ore deposit in Australia. The main iron minerals are goethite (Fe ₂ O ₃ .H ₂ O) and martite (Fe ₂ O ₃ having a magnetite structure). West Angelus ore is a representative iron ore under the brand name (common name). Since there are many fine iron ores with a particle size of 0.25 mm or less, pseudo-granulation property is bad.
The pellet feed is -0.5 mm iron ore fine particles.

The above dust is a general term for fine powder products generated in each step of the iron making process at an ironworks. For example, the dust generated in the sintering process, the blast furnace dust generated in the blast furnace process, and the converter process. Examples include converter dust and converter graphite that are generated, pickling dust generated in cold rolling mills, coke digested sediment powder, rolled return water dust, lagoon dust, and the like. These can use 1 type (s) or 2 or more types. Also, dust generated in processes other than iron making can be used. Specifically, dust generated in thermal power plants, such as fly ash and heavy oil ash, sludge such as calami iron concentrate and copper slag generated in the copper making process, red mud discharged in the alumina manufacturing process, etc. It may be flue gas desulfurization gypsum, asbestos dust, waste toner or the like.

With regard to (2) above, the amount of water is 8.0% by mass or more and 13.0% by mass or less as the amount of water contained in 100% by mass of the iron-making sintered raw material in the selective granulation step. It is possible to sufficiently exhibit the above-described effects, and such a form is also a preferred embodiment. More preferably, it is 8.5% by mass or more and 12.0% by mass or less. More preferably, it is 9.0 mass% or more and 11.0 mass% or less. Moreover, it is preferable that it is 8.0 mass% or more and 13 mass% or less also as the moisture content of the granulated material after selective granulation, Such a form is also one of preferable embodiment of this invention. When the moisture content of the granulated product after selective granulation exceeds 13% by mass, the granulated product may adhere to the granulator wall surface or hopper. A more preferable amount of water is the same as the amount of water contained in 100% by mass of the iron-making sintered raw material in the selective granulation step described above.
In addition, after the selective granulation step, in the step of mixing the granulated product obtained by the step with the remaining sintering raw material for iron making, the amount of moisture contained in 100% by mass of the sintering raw material for iron making in the mixing step The amount is preferably 6.0% by mass or more, and preferably 8.0% by mass or less. More preferably, it is 6.5% by mass or more and 7.5% by mass or less.

Regarding the above (3), for example, quick lime is used as a granulating agent in any of the selective granulation step in the present invention and the step of mixing the granulated product obtained by the step with the remaining sintering raw material for iron making. In this case, (I) without using quick lime in the selective granulation step, the form using quick lime in the step of mixing the selected granulated product with the remaining sintering raw material for iron making, (II) using quick lime in the selective granulation step, In the process of mixing the selected granulated product with the remaining sintering raw material for iron making, in a form that does not use quick lime, (III) Using the quick lime in the selective granulating step, the selected granulated product is mixed with the remaining sintering raw material for iron making In the step of performing, the form using quick lime can be mentioned. In the forms (II) and (III), there are cases where quick lime is used as fine particles having an average particle size of 200 μm or less and cases where it is not. In any of these forms, the present invention can reduce the amount of quicklime added to the sintering raw material for all iron making as compared with the prior art. Moreover, in this invention, it is possible to implement without using quick lime in any of the selective granulation process and the process of mixing the selective granulated product with the remaining sintering raw material for iron making. In the present invention, the amount of quicklime used in the method for granulating a sintered raw material for iron making can be 1.5 parts by weight or less with respect to 100 parts by weight of the sintered raw material for iron making. This is one of the preferred embodiments. More preferably, it is 1.0 part by weight or less, and still more preferably 0.6 part by weight or less.

In the selective granulation step and the step of mixing the selected granulated product with the remaining sintering raw material for iron making in the present invention, granulation using a pan pelletizer, a malmerizer, a drum mixer, an Eirich mixer, a Laedige mixer, etc. In the process of mixing the selected granulated product with the remaining sintering raw material for iron making as described above, the same machine as that used in the selective granulation process may be used, or a different one may be used. However, it is preferable to combine one or more of the above devices in each step.

The granulated product obtained by the granulation treatment method for the iron-making sintered raw material of the present invention can be sintered by a sintering machine to form a sintered ore. Such a sintered ore is a granulated product obtained in the method for granulating a sintered raw material for iron making according to the present invention, that is, at least one selected from the group consisting of a small amount of carboxyl groups, sulfonic acid groups and salts thereof. By adding a high molecular compound having the above group and / or fine particles having an average particle size of 200 μm or less, it is difficult to granulate, and inexpensive ore such as high aluminum ore is used, and quick lime is not used. Or even if it suppresses addition amount, it is useful from the granulated material which can implement | achieve sufficient productivity of a sintered ore.

The productivity of sintered ore production in the present invention can be measured by the product yield and production rate of the sintered ore. For example, the product yield can be measured by sintering after sintering in the sintering pot test. It can be evaluated by measuring the proportion of particles having a particle size of 5 mm or more when 50 kg of ore (sinter cake) is dropped 5 times onto a steel plate from a height of 2 m. The production rate can be calculated by the following equation.
Production rate (t / day / m ² ) = total mass of particles having a particle size of 5 mm or more after product yield evaluation (t) / sintering time (day) / surface area of sintering machine (pan) (m ² )

Below, the high molecular compound which has at least 1 type of group selected from the group which consists of a carboxyl group in this invention, a sulfonic acid group, and these salts is demonstrated. In the polymer compound, a salt of a carboxyl group or a sulfonic acid group is a group having a structure in which a hydrogen atom in a carboxyl group or a sulfonic acid group is replaced with a metal atom or the like, and means a group in the form of a salt. To do.

Examples of the polymer compound include (1) a polymer compound having a carboxyl group and / or a salt thereof, (2) a polymer compound having a sulfonic acid group and / or a salt thereof, and (3) a carboxyl group and / or a salt thereof. And any one or two or more polymer compounds having a sulfonic acid group and / or a salt thereof. As such a polymer compound, at least one monomer selected from the group consisting of a monomer having a carboxyl group, a monomer having a sulfonic acid group, and a monomer having a salt thereof is essential. What can be obtained by superposing | polymerizing the monomer composition made into is preferable. Such monomers can be used singly or in combination of two or more, but more preferably, (1) a monomer having a carboxyl group and / or its relative to 100 mol% of the total monomer composition A monomer composition containing 10 mol% or more of at least one of a monomer having a salt and (2) a monomer having a sulfonic acid group and / or a monomer having a salt thereof is polymerized. Is. If the content of the monomer (1) and / or (2) in the monomer composition is less than 10 mol%, the granulation effect may not be sufficiently obtained in the selective granulation step. More preferably, it is 30 mol% or more, and particularly preferably 50 mol% or more. Among the more preferable polymer compounds, those obtained by polymerizing a composition having a monomer having a carboxyl group and / or a monomer having a salt thereof as an essential component are more preferable. That is, the polymer compound polymerizes a monomer composition containing 10 mol% or more of a monomer having a carboxyl group and / or a salt thereof with respect to 100 mol% of the total monomer composition. More preferably,

The monomer having a carboxyl group or a salt thereof has a carboxyl group such as (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, acrylamide glycolic acid, etc. Monomers and their salts are preferred. These may be used alone or in combination of two or more. Among these, (meth) acrylic acid and / or a salt thereof is more preferable. That is, the polymer compound having a carboxyl group and / or a salt thereof in the present invention is preferably a polymer obtained by polymerization with a monomer composition mainly composed of (meth) acrylic acid and / or a salt thereof. More preferred is acrylic acid and / or a salt thereof. As the salt, alkali metal salts such as sodium and potassium; alkaline earth metal salts such as calcium and magnesium; ammonium salts; Among these, alkali metal salts such as sodium and potassium, and ammonium salts are preferable, and sodium salts are more preferable.

As the monomer having a sulfonic acid group or a salt thereof, a monomer having a sulfonic acid group such as vinyl sulfonic acid, styrene sulfonic acid, sulfoethyl (meth) acrylate, or a salt thereof is preferable. is there. These may be used alone or in combination of two or more.

In addition to the monomer having a carboxyl group, the monomer having a sulfonic acid group, and the monomer having a salt thereof, the above monomer composition includes other copolymers copolymerizable with these monomers. 1 type (s) or 2 or more types of polymerizable monomers may be included.
Examples of the other copolymerizable monomers include 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, 2 -Monomers having an acidic phosphate group such as (meth) acryloyloxyethylphenyl phosphate; monomers having an acid group such as a vinyl acid monomer such as vinylphenol, and salts thereof are preferred.

Examples of the other copolymerizable monomers also include polyalkylene glycol (meth) acrylates such as polyethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, and methoxypolyethyleneglycol monoacrylate; Polyalkylene glycol monoalkenyl ether monomer formed by adding ethylene oxide to methyl-3-buten-1-ol; polyethylene glycol monoethenyl ether monomer formed by adding ethylene oxide to allyl alcohol; A monomer having a polyalkylene glycol chain such as maleic acid polyethylene glycol half ester to which polyethylene glycol has been added is preferred. Among these monomers having a polyalkylene glycol chain, a monomer having a polyalkylene glycol chain having a chain length of 5 mol or more and 100 mol or less in terms of ethylene oxide is easily available, and has a pseudo-graining property. It is preferable from the viewpoint of improvement and polymerizability. More preferably, it is a monomer having a polyalkylene glycol chain having a chain length of 10 mol or more and 100 mol or less in terms of ethylene oxide.

As said other copolymerizable monomer, the following compound can be used besides the thing mentioned above.
Methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid (N, N-dimethylaminoethyl), (meth) acrylic acid (N, N-diethylaminoethyl) C1-C18 (meth) acrylic acid alkyl esters such as aminoethyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (Meth) acrylamide and its derivatives such as (meth) acrylamide; vinyl acetate; styrene; (meth) acrylonitrile; base-containing monomers such as N-vinyl-2-pyrrolidone, vinylpyridine, vinylimidazole; N-methylol (meta ) Crosslinking of acrylamide, N-butoxymethyl (meth) acrylamide, etc. (Meth) acrylamide monomer having hydrolyzability such as vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltriethoxysilane A silane-based monomer in which a group having a direct bond to a silicon atom; a monomer having an epoxy group such as glycidyl (meth) acrylate and glycidyl ether (meth) acrylate; 2-isopropenyl-2-oxazoline, 2- Monomers having an oxazoline group such as vinyl-2-oxazoline; monomers having an aziridin group such as 2-aziridinylethyl (meth) acrylate and (meth) acryloylaziridine; vinyl fluoride, vinylidene fluoride, chloride Single unit having halogen groups such as vinyl and vinylidene chloride (Meth) acrylic acid and polyvalent such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol Multifunctional (meth) acrylic acid ester having a plurality of unsaturated groups in the molecule such as esterified product with alcohol; Multifunctional (meth) acrylamide having a plurality of unsaturated groups in the molecule such as methylenebis (meth) acrylamide; Diallyl phthalate , Diallyl maleate, diallyl fumarate and the like, polyfunctional allyl compounds having a plurality of unsaturated groups in the molecule; allyl (meth) acrylate; divinylbenzene.

When (co) polymerizing the monomer, a chain transfer agent may be used for the purpose of adjusting the molecular weight. Examples of the chain transfer agent include compounds having a mercapto group such as mercaptoethanol, mercaptopropionic acid, t-dodecyl mercaptan; carbon tetrachloride; isopropyl alcohol; toluene; hypophosphorous acid, sodium hypophosphite, sodium bisulfite, etc. A compound having a high chain transfer coefficient is preferred. These may be used alone or in combination of two or more. The amount of the chain transfer agent used is preferably 0.005 to 0.15 mol with respect to 1 mol of the total monomer composition.

Methods for (co) polymerizing the above monomers include various conventionally known polymerization methods such as oil-in-water emulsion polymerization, water-in-oil emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation weight. A combination method, a solution polymerization method, an aqueous solution polymerization method, a bulk polymerization method and the like can be employed. Among these, the aqueous solution polymerization method is preferable from the viewpoint of reduction in polymerization cost (production cost) and safety.

The polymerization initiator used for the polymerization may be a compound that decomposes by heat or a redox reaction to generate radical molecules. Moreover, when performing superposition | polymerization by aqueous solution polymerization method, it is preferable to use the polymerization initiator provided with water solubility. Examples of the polymerization initiator include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; 2,2′-azobis- (2-amidinopropane) dihydrochloride, 4,4′-azobis- (4-cyano Water-soluble azo compounds such as pentanoic acid; thermal decomposable initiators such as hydrogen peroxide; hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalite, potassium persulfate and metal salts, ammonium persulfate and sodium bisulfite A redox polymerization initiator comprising a combination of the above is preferred. These may be used alone or in combination of two or more. What is necessary is just to set suitably as the usage-amount of a polymerization initiator according to a composition, polymerization conditions, etc. of a monomer composition.

The polymerization conditions such as the reaction temperature and reaction time in the above polymerization may be appropriately set according to the composition of the monomer, the type of the polymerization initiator, etc. The reaction temperature is 0 to 150 ° C. Is preferable, and it is more preferable to set it as 40-105 degreeC. The reaction time is preferably about 3 to 15 hours. As a method for supplying the monomer to the reaction system when the polymerization is performed by an aqueous solution polymerization method, a batch addition method, a divided addition method, a component dropping method, a power feed method, or a multistage dropping method can be used. The polymerization may be performed under normal pressure, reduced pressure, or increased pressure.

In the production of the polymer compound, the concentration of the non-volatile component containing the polymer compound contained in the polymer compound aqueous solution obtained when the aqueous solution polymerization method is adopted is preferably 70% by mass or less. When it exceeds 70 mass%, there exists a possibility that a viscosity may become high too much.

Preferable polymer compounds having the sulfonic acid group and / or salt thereof include β-naphthalene sulfonate formalin condensate, melamine sulfonate formalin condensate, aromatic amino sulfonic acid polymer and the like.

The polymer compound having at least one group selected from the group consisting of carboxyl groups, sulfonic acid groups and salts thereof in the present invention preferably has a weight average molecular weight of 1,000 to 1,000,000. If the weight average molecular weight is less than 1000, the action as a dispersant may be reduced. If it exceeds 1,000,000, the viscosity of the polymer compound becomes too high, and it may be difficult to add so that the action as a dispersant is sufficiently exhibited. More preferably, it is 3000 or more and 100000 or less. In the present specification, the weight average molecular weight is a value measured under the following measurement conditions.

(Weight average molecular weight measurement conditions)
Column: Aqueous GPC column “GF-7MHQ” (trade name, manufactured by Showa Denko KK) One carrier liquid: 34.5 g of disodium hydrogen phosphate dodecahydrate and 46.2 g of sodium dihydrogen phosphate dihydrate Ultrapure water is added to make the total amount 5000 g.
Aqueous solution flow rate: 0.5 ml / min
Pump: “L-7110” (trade name, manufactured by Hitachi, Ltd.)
Detector: Ultraviolet (UV) detector “L-7400” (trade name, manufactured by Hitachi, Ltd.), wavelength 214 nm
Molecular weight standard sample: sodium polyacrylate (sodium polyacrylate having a weight average molecular weight of 1300 to 1360000 available from Soka Kagaku)
The analytical sample is prepared by diluting with the carrier liquid so that the polymer compound has a solid content of 0.1% by mass.
However, the following measurement conditions are applied to polymer compounds that cannot be measured under the above measurement conditions.
Model: Waters LCM1
Carrier solution: 115.6 g of sodium acetate trihydrate dissolved in a mixture of 10999 g of water and 6001 g of acetonitrile, and further adjusted to pH 6.0 with 30% aqueous sodium hydroxide solution Flow rate: 0.8 ml / min
Column: Water-based GPC column “TSKgel GuardColumnSWXL + G4000SWXL + G3000SWXL + G2000SWXL” (manufactured by Tosoh Corporation)
Column temperature: 35 ° C
Detector: Waters 410 Differential refraction detector Molecular weight standard sample: Polyethylene glycol The analytical sample is prepared by diluting with the carrier solution so that the polymer compound is 0.1% in solid content.

The polymer compound preferably has a dispersity of 12 or less. If the degree of dispersion exceeds 12, the action of dispersing fine iron ore tends to be small, and the action of making pseudo particles tends to decrease. More preferably, it is 10 or less. The degree of dispersion is the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn), and represents the molecular weight distribution. The number average molecular weight is measured by the same method as the weight average molecular weight.

The method for granulating a sintered raw material for iron making according to the present invention comprises the above-described configuration, and is used for granulating a sintered raw material such as fine iron ore in the production of sintered ore as a raw material for charging a blast furnace in the iron making process. It is effective, and has at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a salt thereof even when an inexpensive ore such as highly granulated or high aluminum ore is used. Even if the addition amount of the polymer compound is suppressed and quick lime is not used or the addition amount is suppressed, a granulated product capable of realizing a sufficient amount of sintered ore production can be obtained.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

All the sintering raw materials used were absolutely dry.
The production rate and product yield in the examples and comparative examples were measured by the following methods.
(Product yield, production rate)
In the product yield, in the sintering pot test, 50 kg of sintered ore after sintering (sinter cake) was dropped 5 times on a steel plate from a height of 2 m. The ratio was evaluated by measuring. The production rate was calculated by the following formula.
Production rate (t / day / m ² ) = total mass of particles having a particle size of 5 mm or more after product yield evaluation (t) / sintering time (day) / surface area of sintering machine (pan) (m ² )

[Example 1]
70000 parts of a sintering raw material (raw material for iron making) having the composition shown in Formulation 1 of Table 1 was prepared. That is, 14113 parts of Formulation 1-A and 55887 parts of Formulation 1-B were prepared. Furthermore, water was added to Formulation 1-A and Formulation 1-B to adjust to 15509 parts (water content 9% by mass) and 59454 parts (water content 6% by mass), respectively.

In Table 1, “MBRPF” is a pellet feed supplied from MBR of a Brazilian mine.
The unit of numerical values in Table 1 is mass% when the sintered new raw material is 100 mass%. In the present invention, the new sintered raw material refers to a sintered raw material for iron making, return ore, fuel, a granulating agent, fine particles having an average particle size of 200 μm or less (however, iron ore, dust generated in a steel plant, (Excluding slag generated in the above).

High-speed stirring mixer (Eirich mixer R05T, Japan) having 15509 parts (water content 9% by mass) of the above-mentioned sintered raw material 1-A, a pan part rotating 350 parts of heavy calcium carbonate having an average particle size of 7 μm and an agitator part Polyacrylic acid having a weight average molecular weight of 6000, which was previously adjusted to a non-volatile content of 4.8% as a polymer compound having a carboxyl group and / or a salt thereof in the composition (sintering raw material). 181 parts of an aqueous sodium solution was sprayed (added) using a spray bottle over about 40 seconds to obtain a selective granulated product. At this time, the rotational speed of the pan 30min ^-1, rotational speed of the agitator was 450min ^-1. Thereafter, 16040 parts of the selective granulated product, 59454 parts of the sintering raw material 1-B (water content 6 mass%), 350 parts of quicklime are put into a drum mixer, and preliminarily stirred for 1 minute at a rotational speed of 24 min ⁻¹ . 500 parts of water was sprayed (added) over 1.5 minutes. After spraying, the mixture was further stirred for 3 minutes at the same rotational speed to perform granulation (pseudo granulation).

The ratio of sodium polyacrylate to the sintering raw material was 0.0125%.
The obtained pseudo particles were fired in a 50 kg scale pan test to obtain a sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a height of 600 mm, a layer thickness of 550 mm, and a suction negative pressure of 9.8 kPa (constant). The production rate of the obtained sintered ore was measured. These results are summarized in Table 2 and Table 3.

[Example 2]
The production rate of sintered ore was measured in the same manner as in Example 1 except that 700 parts of heavy calcium carbonate having an average particle diameter of 7 μm was used instead of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm. These results are summarized in Table 2.

Example 3
The production rate of sintered ore was measured in the same manner as in Example 1 except that 350 parts of heavy calcium carbonate having an average particle size of 7 μm was not used. These results are summarized in Table 2.

Example 4
The production rate of sintered ore was measured in the same manner as in Example 1 except that 350 parts of heavy calcium carbonate having an average particle diameter of 25 μm was used instead of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm. These results are summarized in Table 2.

Example 5
The production rate of sintered ore was measured in the same manner as in Example 1 except that 350 parts of fly ash having an average particle diameter of 17 μm was used instead of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm. These results are summarized in Table 2.

Example 6
Instead of 181 parts of a sodium acrylate aqueous solution having a weight average molecular weight of 6000 adjusted to 4.8% nonvolatile content in advance, 176 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000 adjusted to 2.0% nonvolatile content in advance is used. The production rate of the sintered ore was measured in the same manner as in Example 1 except that. That is, the ratio of sodium polyacrylate to the sintering raw material was 0.005%. These results are summarized in Table 2.

Example 7
The production rate of sintered ore was measured in the same manner as in Example 1 except that 172 parts of water was used instead of 181 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000, which had been adjusted to a non-volatile content of 4.8% in advance. . These results are summarized in Table 2.

Example 8
Instead of adding 350 parts of quicklime and spraying (adding) 500 parts of water over 1.5 minutes, 168 parts of an aqueous sodium polyacrylate solution having a weight average molecular weight of 6000 adjusted to a non-volatile content of 20.8% in advance. Was sprayed (added) over 1.5 minutes in the same manner as in Example 7 to measure the production rate of sintered ore. These results are summarized in Table 2.

Example 9
Instead of 350 parts of calcium carbonate having an average particle diameter of 7 μm, 350 parts of heavy calcium carbonate having an average particle diameter of 25 μm is used, and 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm is used instead of 350 parts of quicklime. Instead of spraying (adding) 500 parts over 1.5 minutes, 168 parts of an aqueous sodium polyacrylate solution having a weight average molecular weight of 6000 adjusted to a non-volatile content of 20.8% in advance is sprayed over 1.5 minutes ( The production rate of the sintered ore was measured in the same manner as in Example 7 except that the addition was performed. These results are summarized in Table 2.

Example 10
70000 parts of a sintering raw material (iron-making raw material) having the composition shown in Formulation 2 of Table 1 was prepared. That is, 9655 parts of Formulation 2-A and 60345 parts of Formulation 2-B were prepared. Furthermore, water was added to Formulation 2-A and Formulation 2-B, and adjusted to 9305 parts (water content 9% by mass) and 65810 parts (water content 6.5% by mass), respectively.

High-speed stirring mixer (Eirich mixer R05T, Japan) having 10610 parts of the above-mentioned sintered raw material 2-A (water content 9% by mass), 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm, and a pan part and an agitator part. Polyacrylic acid having a weight average molecular weight of 6000, which was previously adjusted to a non-volatile content of 11.3% as a polymer compound having a carboxyl group and / or a salt thereof in the composition (sintering raw material). 78 parts of an aqueous sodium solution was sprayed (added) for about 40 seconds using a spray bottle to obtain a selective granulated product. At this time, the rotational speed of the pan 30min ^-1, rotational speed of the agitator was 450min ^-1. Thereafter, 9768 parts of the selective granulated product, 64540 parts of sintered raw material 2-B (water content 6.5 mass%), and 350 parts of quicklime were put into a drum mixer, and pre-stirred for 1 minute at a rotational speed of 24 min ⁻¹ . Thereafter, 450 parts of water was sprayed (added) over 1.5 minutes. After spraying, the mixture was further stirred for 3 minutes at the same rotational speed to perform granulation (pseudo granulation).

The ratio of sodium polyacrylate to the sintering raw material was 0.0125%.
The obtained pseudo particles were fired in a 50 kg scale pan test to obtain a sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a layer thickness of 600 mm, a layer thickness of 550 mm, and a suction negative pressure of 9.8 kPa (constant). The production rate of the obtained sintered ore was measured. These results are summarized in Table 2.

Example 11
70000 parts of a sintering raw material (iron-making material) having the composition shown in Formulation 3 of Table 1 was prepared. That is, 28226 parts of formulation 3-A and 41774 parts of formulation 3-B were prepared. Furthermore, water was added to Formulation 3-A and Formulation 3-B to adjust to 31018 parts (water content 9% by mass) and 44440 parts (water content 6% by mass), respectively.

High-speed stirring mixer (Eirich mixer R05T, Japan) having 31018 parts of the above-mentioned sintered raw material 3-A (water content 9% by mass), 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm and a pan part and an agitator part. Polyacrylic acid having a weight average molecular weight of 6000, which was previously adjusted to a non-volatile content of 9.8% as a polymer compound having a carboxyl group and / or a salt thereof in the composition (sintering raw material). 188.82 parts of an aqueous sodium solution was sprayed (added) for about 40 seconds using a spray bottle to obtain a selective granulated product. At this time, the rotational speed of the pan 30min ^-1, rotational speed of the agitator was 450min ^-1. Thereafter, 31548 parts of this selective granulated product, 44440 parts of sintered raw material 3-B (water content 6 mass%), 350 parts of quicklime were put into a drum mixer, and after pre-stirring for 1 minute at a rotational speed of 24 min ⁻¹ , 50 parts of water was sprayed (added) over 1.5 minutes. After spraying, the mixture was further stirred for 3 minutes at the same rotational speed to perform granulation (pseudo granulation).

The ratio of sodium polyacrylate to the sintering raw material was 0.0264%.
The obtained pseudo particles were fired in a 50 kg scale pan test to obtain a sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a layer thickness of 600 mm, a layer thickness of 550 mm, and a suction negative pressure of 9.8 kPa (constant). The production rate of the obtained sintered ore was measured. These results are summarized in Table 2.

[Comparative Example 1]
In Example 3, 172 parts of water was used instead of 181 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000 adjusted to a non-volatile content of 4.8%, and 840 parts of quick lime was used instead of 350 parts of quick lime. The production rate of sintered ore was measured in the same manner as in Example 3 except that 700 parts of water was used instead of 500 parts of water. These results are summarized in Table 2 and Table 3.

[Comparative Example 2]
A sintered raw material (raw material for iron making) having the composition shown in Formulation 4 of Table 1 was prepared.
Water was added to 70000 parts of the above sintered raw material to adjust it to 74866 parts (water content 6.5%). The mixture (sintering raw material) is charged into a drum mixer, and 438 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000, which has been adjusted to a nonvolatile content of 8% in advance, as a dispersant, is sprayed for about 1.5 minutes. Sprayed (added). The ratio of sodium polyacrylate to the sintering raw material was 0.05%. After spraying, the above-mentioned composition to which the dispersant was added (final composition for granulation treatment) was stirred for 3 minutes at a rotational speed of 24 min ⁻¹ to perform granulation treatment (pseudo granulation). The obtained pseudo particles were fired in a 50 kg scale pan test to obtain a sintered ore. The test conditions were as follows: the sintering pot had a diameter of 300 mm, a layer thickness of 600 mm, and a negative suction pressure of 9.8 kPa (constant). The production rate of the obtained sintered ore was measured. These results are summarized in Table 2.

Example 12
As a polymer compound having a carboxyl group and / or a salt thereof, a sulfonic acid group and / or a salt thereof is used instead of 181 parts of a sodium polyacrylate aqueous solution having a weight average molecular weight of 6000, which has been adjusted to a non-volatile content of 4.8% in advance. The same procedure as in Example 1 was used except that 181 parts of an aqueous solution of sodium polystyrene sulfonate (obtained from Soka Kagaku) with a weight average molecular weight of 70,000 (catalog value) adjusted in advance to a non-volatile content of 4.8% was used as the polymer compound. The production rate of sintered ore was measured. These results are summarized in Table 3.

Example 13
The production rate of sintered ore was measured in the same manner as in Example 1 except that 7 parts of heavy calcium carbonate having an average particle diameter of 7 μm was used instead of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm. These results are summarized in Table 2.

Example 14
In Example 8, in place of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm, 350 parts of heavy calcium carbonate having an average particle diameter of 235 μm was used, and the production rate of sintered ore was increased in the same manner as in Example 8. It was measured. The production rate of sintered ore was 22.9 t / day / m ² .

Example 15
In Example 1, instead of 15509 parts (water content 9% by mass) of Formulation 1-A, 15175 parts (water content 7% by mass) were used, and instead of 500 parts of water added by a drum mixer, water 834 was used. The production rate of the sintered ore was measured in the same manner as in Example 1 except that the part was used. The production rate of sintered ore was 28.6 t / day / m ² .

Example 16
As a compound having a carboxyl group and / or a salt thereof, instead of 181 parts of an aqueous sodium polyacrylate solution having a weight average molecular weight of 6000 adjusted to a non-volatile content of 4.8% in advance, A sodium acrylate / methyl acrylate copolymer having a weight average molecular weight of 33,000 produced by the method described in WO 02/066688 (composition ratio of sodium acrylate to 100 mol% of the total monomer composition is 78.7 mol%) The production rate of sintered ore was measured in the same manner as in Example 1 except that 181 parts of an aqueous solution having a non-volatile content adjusted to 4.8% in advance was used. These results are summarized in Table 3.

Example 17
As a compound having a carboxyl group and / or a salt thereof, a polymer having a sulfonic acid group and / or a salt thereof instead of 181 parts of a sodium acrylate aqueous solution having a weight average molecular weight of 6000, which has been adjusted to a non-volatile content of 4.8% in advance. Sintered in the same manner as in Example 1 except that 181 parts of Mighty 150 (trade name: manufactured by Kao Co., Ltd.), a β-naphthalenesulfonate formalin condensate previously adjusted to a non-volatile content of 9.6%, was used as the compound. The production rate of the ore was measured. These results are summarized in Table 3.

Example 18
In Example 12, 1.9% by mass of serpentine in Formulation 1-B was 1.31% by mass, and 16.19% by mass of limestone was 16.78% by mass. Further, 350 parts of talc having an average particle diameter of 20 μm was used instead of 350 parts of heavy calcium carbonate having an average particle diameter of 7 μm. Other than these, the production rate was measured in the same manner as in Example 12. As a result, the production rate was 28.2 t / day / m ² .

In Tables 2 and 3, “mass%” is mass% with respect to all iron-making sintered raw materials. For those marked with “Note 1”, it means that they were added using a drum mixer.

Claims (11)

When granulating a sintered raw material for iron making containing fine iron ore, after the selective granulation step in which a part of the sintered raw material for iron making is preliminarily granulated, the granulated product obtained by the step is left as a residual material. A method for granulating a sintered raw material for iron making comprising a step of mixing with a sintered raw material for iron making,
The selective granulation step is performed using a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof, and / or fine particles having an average particle size of 200 μm or less. Ri vegetables and grain processing,
When the polymer compound is used at least in the selective granulation step, the amount of the polymer compound used is 0.001% by mass or more and 0.5% by mass in terms of a mass ratio with respect to 100% by mass of all the raw materials for iron making sintering. And
When at least the fine particles having an average particle size of 200 μm or less are used in the selective granulation step, the amount of the fine particles used is iron ore having an average particle size of 200 μm or less, and dust generated in an iron mill having an average particle size of 200 μm or less. And the sum total of those excluding slag generated in an iron mill having an average particle size of 200 μm or less is 0.05% by mass or more and 10% by mass or less in terms of a mass ratio with respect to 100% by mass of all the ironmaking sintered raw materials <br / > A method for granulating a sintering raw material for iron making, characterized in that: The fine particles having an average particle size of 200 µm or less are at least one selected from the group consisting of calcium carbonate, fly ash, kaolin clay, silica, talc, bentonite, silica fume, and anhydrous gypsum. The granulation method of the sintering raw material for iron manufacture of 1. When granulating a sintered raw material for iron making containing fine iron ore, after the selective granulation step in which a part of the sintered raw material for iron making is preliminarily granulated, the granulated product obtained by the step is left as a residual material. A method for granulating a sintered raw material for iron making comprising a step of mixing with a sintered raw material for iron making,
The selective granulation step is a granulation treatment using a polymer compound having at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group and a salt thereof, and fine particles having an average particle size of 200 μm or less. Ri name and,
When the polymer compound is used at least in the selective granulation step, the amount of the polymer compound used is 0.001% by mass or more and 0.5% by mass in terms of a mass ratio with respect to 100% by mass of all the raw materials for iron making sintering. And
When at least the fine particles having an average particle size of 200 μm or less are used in the selective granulation step, the amount of the fine particles used is iron ore having an average particle size of 200 μm or less, and dust generated in an iron mill having an average particle size of 200 μm or less. And the sum total of those excluding slag generated in an iron mill having an average particle size of 200 μm or less is 0.05% by mass or more and 10% by mass or less in terms of a mass ratio with respect to 100% by mass of all the ironmaking sintered raw materials <br / > A method for granulating a sintering raw material for iron making, characterized in that: The polymer compound polymerizes a monomer composition containing 10 mol% or more of a monomer having a carboxyl group and / or a salt thereof with respect to 100 mol% of the total monomer composition. The method for granulating a sintered raw material for iron making according to claim 1 or 2. The sintered material for iron making according to claim 1, 2 or 4, wherein the sintered raw material for iron making to be granulated in the selective granulation step contains 5 to 60% by mass of the sintered raw material for iron making. Raw material granulation method. The granulation treatment of the sintering raw material for iron making according to claim 1, 2, 4, or 5, wherein the moisture content of the granulated product after selective granulation is 8.0 mass% or more and 13 mass% or less. Method. In the selective granulation step, a hardly granulated raw material selected from the group consisting of maramamba ore, pellet feed and a raw material containing 40% or more of fine powder of 1 mm or less is included in 100% by mass of the sintering raw material in the selective granulation step. The method for granulating a sintering raw material for iron making according to claim 1, 2, 4, 5, or 6 , characterized by comprising 10% by mass or more. The selective granulation step is a granulation treatment using the polymer compound and fine particles having an average particle diameter of 200 μm or less.
The granulation processing method of the sintering raw material for iron manufacture of Claim 1, 2, 4, 5, 6 or 7 characterized by the above-mentioned. The method for granulating the sintered raw material for iron making uses quick lime in the step of mixing the granulated product obtained by the selective granulation step and / or the selective granulation step with the remaining sintered raw material for iron making.
The granulation processing method of the sintering raw material for iron manufacture in any one of Claims 1-8 characterized by the above-mentioned. The method for granulating a sintered raw material for iron making does not use quick lime in the selective granulation step, but uses quick lime in the step of mixing the granulated product obtained by the selective granulation step with the remaining sintered raw material for iron making.
The granulation processing method of the sintering raw material for iron manufacture of Claim 9 characterized by the above-mentioned. The step of mixing the granulated product obtained by the selective granulation step with the remaining sintering raw material for iron making is 0.1 parts by weight or more of quick lime with respect to 100 parts by weight of the sintering raw material for iron making in the step. Use less than 5 parts by weight
The method for granulating a sintered raw material for iron making according to claim 9 or 10.